Space is not a perfect vacuum, especially near Earth orbit. It is close to a vacuum, but there are still some trace gasses and dust running around. These particles collect on the outsides of the suits and, when brought back inside, smell strongly. The smell is the actual smell of space.

If it ever did get made I'd imagine it would just end up being like Saint's Rows character customization where you can change you character to look like anything you want, but ultimately their appearance has no bearing on the gamplay. The only distinction between the characters will likely be which set of pre-made special moves you pick. In which case it's going to terrible, because there's no way you're going to have balanced gameplay in a game where one guy is playing as a soldier and the other is superman.